Balls for use in baseball and softball

ABSTRACT

Balls are provided for use in baseball or softball, including, for example, a solid sphere, an outer shell of a foamed material, covering the solid sphere, and a material covering the outer surface of the shell. Methods for making a ball and a ball core are also described.

This is a divisional application of U.S. application Ser. No.10/641,271, filed Aug. 14, 2003, now pending, which claims benefit fromU.S. Provisional Application No. 60/440,518, filed Jan. 16, 2003, nowexpired. The entire disclosures of both applications are incorporatedherein by reference.

TECHNICAL FIELD

This invention relates to balls for use in baseball and softball.

BACKGROUND

The invention relates to balls, e.g., substitute baseballs, softballsand the like, and to methods for making balls.

Regulation baseballs and softballs typically include a cork and rubbercore surrounded with yarn windings and a leather cover. Regulationbaseballs and softballs are quite hard and can cause serious injury,especially to younger and/or inexperienced ballplayers. It is thereforedesirable to significantly reduce the chance of injury by providingballs that are softer. Various substitute baseballs and softballs havebeen proposed to address the need for balls that are softer and thussafer than regulation balls. It is important, however, to maintain theperformance, durability, and the “look and feel” of substitute balls sothat they can function as suitable training balls, and so that theplayers' enjoyment of the game is not diminished by the feeling that theball is not a regulation ball.

One type of ball that has been used for baseball and softball trainingand recreation includes a mixed rubber and cork core in a hollow sphereform with a layer covering the sphere. The softness and bounce of theball can be adjusted by increasing or decreasing the number and the sizeof the pieces of cork in the mixture, and/or by adjusting the wallthickness of the hollow sphere. When struck by a bat, these ballsgenerally sound to the players similar to that of the regulation ballsdiscussed above. However, after certain types of impacts, such as theball being hit by the bat, the mixed rubber and cork core can beshattered or cracked apart easily. In order to increase durability, thehollow core may be replaced by a solid core. However, this will producea relative increase in hardness which may compromise safety.

Others types of baseballs include a core formed of a softer material,such as urethane foam, polyurethane (PU) foam, or rubber foam. Forexample, U.S. Pat. No 4,772,019 discloses a game ball formed with asoft, resilient, substantially closed-cell plastic foam core. Theseballs can be adjusted to be softer than those having a mixed rubber/corkcore, and will typically last longer by comparison, but do not providethe player with the feel of a regulation ball while playing.

SUMMARY

In one aspect, the invention features a ball for use in baseball orsoftball including an inner sphere, an outer shell of a foamed material,covering the solid sphere, and a material covering the outer surface ofthe shell.

Embodiments may include one or more of the followings features. Theinner sphere is solid. The sphere includes a mixture of a polymer andpieces of cork. The polymer is selected from the group consisting ofpolyurethane, rubber, and mixtures thereof. The outer shell comprises apolymer selected from the group consisting of polyurethane, EVA, andmixtures thereof. The material covering the outer surface of the shellcomprises two panels of material that are stitched together. Thematerial covering the outer surface of the shell is selected from thegroup consisting of genuine leather, rubber, fabric, PVC, PU, and TPU.The two panels comprise sheets of fabric material with an EVA foambacking. The two panels are bonded by an extra knitted fabric along theedges and stitched together to provide a high seam effect. The materialcovering the outer surface of the shell includes a layer of rubbermolded and vulcanized over the surface. The ball has the dimensions andappearance of a regulation ball.

In another aspect, the invention features a method of making a ball foruse in softball or baseball, including: (a) blending a core polymer withpieces of cork to form a blended mixture; (b) molding and heating theblended mixture to form a sphere; (c) injecting a foamable polymer intoa mold under conditions so that the polymer will form a foam shell; and(d) applying the foam shell to the sphere.

Embodiments of this aspect of the invention may include one or more ofthe following features. The sphere is solid. The method further includes(e) molding and heating the sphere and the shell to form a core suitablefor use in a ball. The applying step includes applying an adhesive to asurface of the solid sphere. The core polymer includes rubber. Themolding step further comprises vulcanizing the rubber. The core polymermay include polyurethane. The injecting step includes forming twohemispherical shell portions. The method further includes wrapping thecore with a cover. The wrapping step comprises wrapping the ballmaterial with two panels of fabric material with EVA foam backing. Themethod further includes bonding the panels by an extra knitted fabricalong the edges and stitching together to provide a high seam effect.The wrapping step includes wrapping the ball material with a rubberlayer. The method further includes vulcanizing the rubber layer.

Among the advantages of the invention are the following. The balls havegood durability and safety. The characteristics of the foamed shell canbe controlled over a broad range that allows the amount of rebound orbounce of the ball to be accurately controlled by changing the foamdensity. The inclusion of the foam shell tends to reduce the chance ofinjury to a player struck by the ball, compared, for example, with aball having the whole core made from solid rubber. Moreover, the foamedmaterial is softer than the inner sphere of the core and thus can absorbthe external impacts, e.g. baseball batting. The balls can generally beplayed for a longer time than a similar ball without the foamed shell.In embodiments in which the solid inner sphere is made of a mixture ofrubber or polyurethane and cork, the ball will generally produce a cracksound similar to that produced by a regulation baseball or softball. Insome implementations, the ball has a feel that is similar to that of aregulation baseball or softball, which will tend to increase theplayers' enjoyment of the game.

To further enhance the safety of the invention for the young players,especially for children, in some implementations the ball is covered bya layer of fabric with EVA foam backing. A fabric cover with an EVA foambacking provides further softness of the ball for the players. Extracloth may be bound along the edges of the fabric panels, to create ahigh seam effect after the edges of the fabric panels are stitchedtogether. This high seam effect provides good gripping and control for abeginner or trainee.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view of a ball.

FIG. 2 is a view of a core of a ball.

FIGS. 3A-3B are a cross-sectional view of a mold to an inner sphere ofthe core.

FIG. 4 is a cross-sectional view of a method of making a core shell.

FIG. 5 is a cross-sectional view of forming the sphere.

FIG. 6 is a view of a second example of a ball.

FIG. 7 is a view of a third example of a ball.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a ball 14, used in baseball or softball,includes a core 10. Core 10 is covered with two panels 15, 16 that arestitched together with a durable thread 17 (e.g., nylon, polyester orvinyl thread). Core 10 includes a solid, inner sphere 13 placed withintwo hemispherical outer core shells 11, 12, each having a wall thicknessT.

The construction of core 10 and the material used to form core 10enables a ball to be durable and safe while also providing the “look andfeel” of a regulation ball.

The inner sphere is formed of a mixture of a polymer, such aspolyurethane or rubber, and pieces of cork. The cork pieces may be ofany desired size. The polymer mixture generally includes other,non-resilient, processing components that are selected to bind thepieces of cork together upon heating of the polymer mixture. The innersphere preferably has a diameter of about 3.0-8.0 cm, and weighs about50-80 grams.

The outer shell is formed of a foamed polymeric material, preferablypolyurethane or ethylene vinyl acetate (EVA). The outer shell preferablyhas a wall thickness T of 1.0-2.0 cm, and weighs about 50-90 grams.Examples of suitable properties for a 9″ baseball and a 12″ softball aregiven below. The density of the outer shell and/or the inner sphere mayvary for balls of other sizes.

9″ Baseball:

-   -   Whole core diameter—7.07-7.18 cm    -   Whole core weight—104-114 gm    -   Thickness of the outer shell—1.0 cm    -   Density of the shell—0.4-0.54 gm/cm³    -   Density of the inner sphere—0.7-0.84 gm/cm³    -   C.O.R.—0.42 *

12″ Softball:

-   -   Whole core diameter—9.4-9.5 cm    -   Whole core weight—136-144 gm    -   Thickness of the outer shell—1.2 cm    -   Density of the shell—0.2-0.37 gm/cm³    -   Density of the inner sphere—0.28-0.45 gm/cm³    -   C.O.R.—0.53 *

C.O.R. (Coefficient of Rebounce) is equal to the measured rebounce of aball after a free drop to the ground from 2 meter height.

The density and bounce characteristics can be changed to suit particularapplications. For example, the density of the outer shell can be variedby adjusting the amount of sponging agent included in the foamedpolymeric material, while the density of the inner sphere can be variedby adjusting the size and/or number of the cork pieces.

The shell is generally adhered to the outer surface of the inner sphereby an adhesive or glue, as will be described below. However, if desired,other techniques of joining the sphere and shell may be employed.

The core (inner sphere and shell) preferably weighs about 100-170 gramsin total, depending on the requirements of the players.

The cover is made of a sheet material such as genuine leather, fabric,poly vinyl chloride (PVC), poly urethane (PU), or thermoplasticpolyurethane (TPU). The cover may consist of separate panels of materialstitched together or may be formed from molded rubber.

Referring to FIGS. 3A-3B, inner sphere 13 is formed by forming a mixture26 such as mixing rubber and cork (for a baseball), or a urea/melamineadhesive and latex blend and cork (for a softball), together with otherprocess components (see examples below) that bind the cork and polymertogether by open rolling and kneading. For example, in constructing abaseball, mixture 26 has the following ingredients: Component Weight (g)Weight % Natural Rubber 4.25 7.359 Reclaimed (Natural) Rubber 12.7422.061 Light Calcium 3.77 6.528 Yellow Oil 0.42 0.727 Sulfur 0.51 0.883Zinc Oxide 0.68 1.177 Stearic Acid 0.51 0.883 Dibenzothiozyl Disulfide0.31 0.537 Accelerator for Rubbers 0.25 0.433 Rubber anti-aging agent0.34 0.589 Cork 33.97 58.823

In another example, in constructing a softball, mixture 26 has thefollowing ingredients: Component Weight (g) Weight % Cork 67.33 76.338Urea-melamine Adhesive 13.47 15.272 Latex 6.73 7.630 Anti-bacteria agent0.67 0.760

Mixture 26 is placed into a concave hemispherical mold 27 and covered byanother concave hemispherical mold 28. The two concave hemisphericalmolds 27, 28 are locked together by clamps 29 and 30 to mold the mixture26 inside in a solid spherical shape. Mixture 26 is heated in molds 27,28, e.g., at 140° C. for 15-20 minutes. The molded mixture 26 is cooledand removed from molds 27, 28 to form inner sphere 13. In thisembodiment, inner sphere 13 has a diameter of 3.0-5.3 cm for a baseballand 5.7-8.0 cm for a softball.

Referring to FIG. 4, two hemispherical core shells, 11, 12 are formed bymixing together polyurethane along with other components, such as thoseshown below to form a polyurethane mixture 31. For example, inconstructing a baseball or softball, the following ingredients may beused to form mixture 31. Component Ratio (g) Polyether Polyol 100Methylene Bisphenyl Isocyanate (MDI) 20-55 Water 0.5-2.5 Diazobicyclo(2.2.2) octance (DABCO) 0.1-0.3 Dibutyltin Dilaurate (T-9) 0.08-0.23Silicone oil 0.2-0.8

In the aforesaid formula, water is used as a sponging agent, DABCO & T-9as an accelerator, and silicone oil as a stabilizer.

Mixture 31, in liquid form, is injected into a set of molds 32 (FIG. 4).Heating mixture 31 at 50° C. for 15-20 minutes inside mold 32 causes achemical reaction, causing mixture 31 to foam. The mixture is allowed tofill the mold, after which the finished hemispherical shell is removedfrom the molds to form outer shell 12. The process is repeated to formouter shell 11. In this embodiment, the hemispherical shell has a wallthickness of 1.0-2.0 cm.

Referring to FIGS. 5A and 5B, circumferential edges 33 & 34 of theresulting hemispherical shells are sanded to provide a rough surface. Athin glue or adhesive 35, which is a kind of glue as well as a curingagent under the heating process described hereunder, is applied over thesurface of the inner sphere 13 and the inner surfaces of thehemispherical outer shell 11 and 12 respectively and then heated at atemperature of 70° C. for 10 minutes to accelerate the curing process:The inner sphere 13 is placed on the inner surface of hemisphericalouter shell 12 and covered by hemispherical outer shell 11 (FIG. 5) foranother 10 minutes while the curing process is still going on. The innersphere 13 and the outer shells 11 and 12 are then adhered under thecuring process and core 10 is formed. The outer surface of the resultingcore 10 is buffed and sanded. Core 10 is covered by panels 15, 16 whichare stitched together.

In other embodiments, core 10 can be placed in other constructed balls.For example, in FIG. 6, a ball 18 is formed by covering core 10 with twopanels of material 19, 20, e.g. knitted fabric and an EVA backing, thatare bonded together by an extra knitted fabric 21 and stitched togetherwith durable thread 22 (e.g., nylon, polyester or vinyl thread). Thematerial is formed by laminating a layer of EVA foam underneath a fabricsheet. The material is cut into two panels in the shape of regularbaseball or softball cover. The edge of each fabric panel is then boundby the extra cloth 21, and the edges of the fabric panels are stitchedtogether so as to form a ball cover having a high seam effect, i.e., theseam is raised above the surface of the ball, due to the extra clothlayer at the seam.

In another embodiment, a ball 23 is formed by covering core 10 with alayer of rubber 24 that is molded with a raised stitching pattern 25 tosimulate the stitching of a regulation baseball or softball.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A ball for use in baseball or softball comprising: (a) an innersphere, (b) an outer shell of a foamed material, covering the innersphere, and (c) a material covering the outer surface of the shell. 2.The ball of claim 1 wherein the inner sphere is solid.
 3. The ball ofclaim 1 wherein said sphere comprises a mixture of a polymer and piecesof cork.
 4. The ball of claim 3 wherein the polymer comprises rubber. 5.The ball of claim 1 wherein the outer shell comprises a polymer selectedfrom the group consisting of polyurethane, EVA, and mixtures thereof. 6.The ball of claim 1 wherein the material covering the outer surface ofthe shell comprises two panels of material that are stitched together.7. The ball of claim 1 wherein the material covering the outer surfaceof the shell is selected from the group consisting of genuine leather,fabric, rubber, PVC, PU, and TPU.
 8. The ball of claim 7 wherein the twopanels comprise sheets of fabric material with an EVA foam backing. 9.The ball of claim 8 wherein the two panels are bonded by an extraknitted fabric along the edges and stitched together to provide a highseam effect.
 10. The ball of claim 1 wherein said material covering theouter surface of the shell comprises a layer of rubber molded andvulcanized over the surface.